DNA-guided DNA interference by a prokaryotic Argonaute.
DNA-guided DNA interference by a prokaryotic Argonaute.
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原核生物 Argonaute 进行 DNA 引导 DNA 干扰
DOI：
10.1038/nature12971
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发表时间：
2014-03-13
期刊：
影响因子：
64.8
通讯作者：
van der Oost J
中科院分区：
文献类型：
--
作者：
Swarts DC;Jore MM;Westra ER;Zhu Y;Janssen JH;Snijders AP;Wang Y;Patel DJ;Berenguer J;Brouns SJJ;van der Oost J
RNA干扰广泛分布于真核生物中，具有多种功能，包括抗病毒防御和基因调控。所有 RNA 干扰途径均使用小单链 RNA (ssRNA) 分子，引导 Argonaute (Ago) 家族的蛋白质与互补的 ssRNA 靶标：RNA 引导的 RNA 干扰。尽管生物信息学分析表明原核 Ago 变体参与宿主防御，但其作用仍然难以捉摸。在这里，我们证明了嗜热栖热菌 (TtAgo) 细菌的 Ago 作为外源 DNA 的吸收和传播的屏障。在体内，TtAgo 装载有 5'-磷酸化 DNA 引导物，长度为 13-25 个核苷酸，大部分来自质粒，并且对 5' 端脱氧胞苷具有强烈的偏向性。这些小干扰 DNA 引导 TtAgo 切割互补 DNA 链。因此，尽管 TtAgo 与其真核对应物具有结构同源性，但它通过 DNA 引导的 DNA 干扰在宿主防御中发挥作用。
RNA interference is widely distributed in eukaryotes and has a variety of functions, including antiviral defence and gene regulation. All RNA interference pathways use small single-stranded RNA (ssRNA) molecules that guide proteins of the Argonaute (Ago) family to complementary ssRNA targets: RNA-guided RNA interference. The role of prokaryotic Ago variants has remained elusive, although bioinformatics analysis has suggested their involvement in host defence. Here we demonstrate that Ago of the bacterium Thermus thermophilus (TtAgo) acts as a barrier for the uptake and propagation of foreign DNA. In vivo, TtAgo is loaded with 5′-phosphorylated DNA guides, 13–25 nucleotides in length, that are mostly plasmid derived and have a strong bias for a 5′-end deoxycytidine. These small interfering DNAs guide TtAgo to cleave complementary DNA strands. Hence, despite structural homology to its eukaryotic counterparts, TtAgo functions in host defence by DNA-guided DNA interference.